The Ampex MM-1100 and MM-1200 machines are similar in a lot of respects, and many of the parts are interchangeable. Having rebuilt two MM-1200s and two MM-1100s, and parted out a few others in the process, I’ve had more first-hand experience of the similarities and differences than most people would want. This list will be useful to anyone who is wondering if they can get away with using a part from the other model.
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Item
|
Interchangeable?
|
Comments
|
||
|
Yes
|
Modify
|
No
|
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| Transport | ||||
| Capstan |
*
|
Different connectors | ||
| Capstan servo card |
*
|
Basic card interchangeable; constant tension MM-1200 will require the daughter board | ||
| Counter (mechanical) |
*
|
Only used on early MM-1100s | ||
| Counter (onboard electronic) | * | MM-1100 counter is hard-wired to transport card bay; MM-1200 counter has connector | ||
| Counter (outboard electronic) |
*
|
Only used on certain MM-1100s, never on MM-1200 | ||
| Guides |
*
|
Fixed posts on earlier MM-1100s | ||
| Head assembly |
*
|
Plastic cover on MM-1100 | ||
| MDAs |
*
|
Do not be fooled by the connector being the same for both machines – the wiring is significantly different (guess how I know) | ||
| Pinch roller assembly |
*
|
|||
| Pinch wheel rotary solenoid |
*
|
|||
| Tape lifter assembly |
*
|
|||
| Tension arm assembly |
*
|
|||
| Torque motor (supply) | * | Early MM-1100s with mechanical counter have direction change sensor mounted on the motor | ||
| Torque motor (takeup) | * | |||
| Transport control card |
*
|
Apparently can be done | ||
| Transport extender card |
*
|
More keying slots on MM-1200 | ||
| Audio | ||||
| Audio cards |
*
|
Very similar revisions. Probably best to have correct repro cards though (different xformer ratio) | ||
| Audio extender cards |
*
|
2-sided bias/erase extender is needed if PURC cards fitted | ||
| Channel bays |
*
|
|||
| Input accessory dummy plug (replaces transformer) |
*
|
May need different wiring – check with manual | ||
| Input transformers |
*
|
|||
| Switcher card relays |
*
|
MM-1200 used Make Before Break | ||
| Switcher cards |
*
|
|||
| VU meters |
*
|
Completely different rear form factor and mounting arrangement | ||
| Wiring looms |
*
|
Some similarities, but all different connectors | ||
| Miscellaneous | ||||
| Control panel (full) |
*
|
|||
| Control panel (transport only) |
*
|
Minor (but crucial!) wiring changes | ||
| Doors |
*
|
MM-1200 has stops to prevent them from opening too far | ||
| Input-output panel |
*
|
Different connectors | ||
| Operation and maintenance manual |
*
|
|||
| Power supply assembly |
*
|
MM-1200 is single assembly whereas MM-1100 has one assembly for each regulator card | ||
| Power supply regulator cards | * | |||
| Remote cable |
*
|
|||
| Side panels |
*
|
Not interchangeable if MM-1100 is 16 or 8 track (since it is shorter) | ||
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